Tyler Chicoine now says he saw his former girlfriend, Nytosha Laforce, violently shaking the toddler before his death

The former boyfriend of the Winooski woman charged with murdering her son admits he lied to police.

Tyler Chicoine, 28, pleaded guilty to charges of giving false information to a police officer in connection with the death of 14-month-old Peighton Geraw.

Chicoine is the former boyfriend of Geraw's biological mother Nytosha Laforce.

Laforce has pleaded not guilty to Peighton's murder.

In court, Chicoine admitted he didn't tell police what he says really happened the day Geraw died until weeks into the investigation.

He told law enforcement officers last month that he saw Laforce violently shaking the toddler just hours before his death.

Now the prosecution says he'll be their key witness in the murder trial against Laforce.

“I'm happy that he spoke up now, but I wish that he would have did it on the day he was asked instead of 3, 4 interviews and still lying,” Tyler Chicoine’s sister Nicole Chicoine said.

Tyler Chicoine's mother and sister sat quietly while he admitted in open court he knowingly withheld information from police.

Geraw died on April 4, but police say it wasn't until May that Tyler Chicoine would tell the whole story about what he says happened the day the toddler died.

“He said clearly and demonstrated that he saw Nytosha Laforce violently shake Peighton Geraw and slammed Peighton Geraw's head against the floor in the house. That account was corroborated by the medical examiner as the likely cause of death,” Chittenden Co. State’s Attorney TJ Donovan said.

According to court documents, Tyler Chicoine spoke to officers four times, but it wasn't until he was polygraphed in the third and fourth interviews that he began to reveal the details about his former girlfriend saying, he had never seen her "this crazy and violent before,” adding, "she was definitely on something, and it wasn't just weed," and "it was like she wasn't there."

“He was such a good baby. He was the best baby ever,” Nicole Chicoine said.

And while Tyler Chicoine prepares to be the prosecution's primary witness in the murder trial against his former girlfriend, his family is still healing.

“A long road and it's been hard, and it'll probably still be hard. For probably the rest of my life,” Nicole Chicoine said.

As part of his plea agreement, Tyler Chicoine will be released from prison. He was incarcerated after Geraw’s death for a parole violation.

Tyler Chicoine also agreed to cooperate with the prosecution of Laforce and said he would not have any contact with her.

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and beyond, you're watching wptz newschannel five, this is newschannel five at 6.. THE FORMER BOYFRIEND OF THE WINOOSKI WOMAN CHARGED WITH MURDERING HER SON ADMITS HE LIED TO POLICE. GOOD EVENING IM STEPHANIE GORIN. GEORGE IS OFF. TWENTY- EIGHT-YEAR-OLD TYLER CHICOINE PLEADED GUILTY TO CHARGES OF GIVING FALSE INFORMATION TO A POLICE OFFICER IN CONNECTION WITH THE DEATH OF 14-MONTH-OLD PEIGHTON GERAW. CHICOINE IS THE FORMER BOYFRIEND OF GERAW'S BIOLOGICAL MOTHER NYTOSHA LAFORCE. LAFORCE HAS PLEADED NOT GUILTY TO PEIGHTON'S MURDER. WPT'Z BRIDGET SHANAHAN WAS IN COURT TODAY AND JOINS US NOW LIVE WITH MROE, BRIDGET? STEPH -- IN COURT TODAY -- TYLER CHICOINE ADMITTED HE DIDN'T TELL POLICE WHAT HE SAYS REALLY HAPPENED THE DAY PEIGHTON DIED UNTIL WEEKS INTO THE INVESTIGATION. HE TOLD LAW ENFORCEMENT OFFICERS LAST MONTH THAT HE SAW HIS FORMER GIRLFRIEND, NYTOSHA LAFORCE, VIOLENTLY SHAKING THE TODDLER JUST HOURS BEFORE HIS DEATH. AND NOW THE PROSECUTION SAYS HE'LL BE THEIR KEY WITNESS IN THE MURDER TRIAL AGAINST LAFORCE. 51.02 :09 NICOLE CHICOINE/TYLER' S SISTER I'm happy that he now spoke up but I wish that he would have did it on the day he was asked instead of 3, 4 interviews and still lying. TYLER CHICOINE'S spoke up but I wish that he would have did it on the day he was asked instead of 3, 4 interviews and still lying. S SISTER I'm happy that he now spoke up but I wish that he would have did it on the day he was asked instead of 3, 4 interviews and still lying. TYLER CHICOINE'S MOTHER AND SISTER SAT QUIETLY WHILE HE ADMITTED IN OPEN COURT HE KNOWINGLY WITHHELD INFORMATION FROM POLICE. NATS GUILTY?? 14-MONTH-OLD- PEIGHTON GERAW DIED ON APRIL 4TH -- BUT POLICE SAY IT WASN'T UNTIL MAY THAT CHICOINE WOULD TELL THE WHOLE STORY ABOUT WHAT HE SAYS HAPPENED THE DAY THE PEIGHTON DIED. 49.11 TJ DONOVAN/STATE' S ATTORNEY he said clearly and demonstrated that he saw Nytosha Laforce violently shake Peighton Geraw and slammed Peighton Geraw's head aginst the floor in the house. That account was corraborated by the medical examiner as the likely cause of death. ACCORDING TO THE AFFIDAVIT -- CHICOINE SPOKE TO OFFICERS FOUR TIMES -- BUT IT WASN'T UNTIL HE WAS POLYGRAPHED IN UNTIL HE WAS POLYGRAPHED IN THE THIRD AND FOURTH INTERVIEWS THAT HE BEGAN TO REVEAL THE DETAILS ABOUT HIS FORMER GIRLFRIEND SAYING, HE HAD NEVER SEEN HER "THIS CRAZY AND VIOLENT BEFORE." ADDING, "SHE WAS DEFINITELY ON SOMETHING, AND IT WASN'T JUST WEED." AND "IT WAS LIKE SHE WASN'T THERE." 47.35 :20 BRIDGET: if tyler had been honest about what he saw sooner, do you think Peighton would still be alive? DONOVAN: You know, I can't answer that question at this time. I mean clearly because of Mr. Chicoine's earlier statements to the police this investigation was delayed and deflected from Ms. Laforce. 51.16 :11 NICOLE He was such a good baby. This has been really hard for your family? Yeah, really hard. Like he was the best baby ever. AND WHILE CHICOINE PREPARES TO BE THE PROSECUTION'S PRIMARY WITNESS IN THE MURDER TRIAL AGAINST HIS FORMER GIRLFIEND -- HIS FAMILY IS STILL HEALING... 52.14 :07 NICOLE A long road. And it's been hard, and it'll probably still be hard. For probably the rest of my life, you know. AS PART OF HIS PLEA AGREEMENT -- CHICOINE WILL BE RELEASED FROM PRISON HE WAS INCARCERATED AFTER PEIGHTON'S DEATH FOR A PAROLE VIOLATION. CHICOINE ALSO AGREE TO COOPERATE WITH THE PROSECUTION OF LAFORCE AND PROMISED NOT TO HAVE ANY CONTACT WITH HER. BRIDGET SHANAHAN WPTZ